Lithium batteries are prepared from one or more lithium electrochemical cells. Such cells have included an anode (negative electrode) of metallic lithium, a cathode (positive electrode) typically a transition metal chalcogenide, and an electrolyte interposed between electrically insulated, spaced apart, positive and negative electrodes. The electrolyte typically comprises a salt of lithium dissolved in one or more solvents, typically nonaqueous (aprotic) organic solvents. By convention, during discharge of the cell, the negative electrode of the cell is defined as the anode. During use of the cell, lithium ions (Li+) are transferred to the negative electrode on charging. During discharge, lithium ions (Li+) are transferred from the negative electrode (anode) to the positive electrode (cathode). Upon subsequent charge and discharge, the lithium ions (Li+) are transported between the electrodes. Cells having metallic lithium anode and metal chalcogenide cathode are charged in an initial condition. During discharge, lithium ions from the metallic anode pass through the liquid electrolyte to the electrochemically active material of the cathode whereupon electrical energy is released. During charging, the flow of lithium ions is reversed and they are transferred from the positive electrode active material through the ion conducting electrolyte and then back to the lithium negative electrode.
The lithium metal anode has been replaced with a carbon anode, that is, a carbonaceous material, such as non-graphitic amorphous coke, graphitic carbon, or graphites, which are intercalation compounds. This presents a relatively advantageous and safer approach to rechargeable lithium as it replaces lithium metal with a material capable of reversibly intercalating lithium ions, thereby providing the "rocking chair" battery in which lithium ions "rock" between the intercalation electrodes during the charging/discharging/recharging cycles. Such lithium metal free cells may thus be viewed as comprising two lithium ion intercalating (absorbing) electrode "sponges" separated by a lithium ion conducting electrolyte usually comprising a lithium salt dissolved in nonaqueous solvent or a mixture of such solvents. Numerous such electrolytes, salts, and solvents are known in the art. Such carbon anodes may be prelithiated prior to assembly within the cell having the cathode intercalation material.
Lithium manganese oxide represented by the nominal general formula LiMn.sub.2 O.sub.4 is known to be an intercalation compound usable as a cathode material in a lithium battery. This material has been used as a positive electrode for batteries comprising lithium metal anodes as well as a positive cathode lithium source for lithium ion batteries, for example, comprising intercalation carbon electrodes as anodes.
Methods of synthesis for LiMn.sub.2 O.sub.4 compounds are known and are reactions generally between stoichiometry quantities of a lithium containing compound and a manganese containing compound, exemplified by a lithium salt and manganese oxide. Common precursors are, for example, lithium salt and MnO.sub.2 compounds as disclosed by Hunter in U.S. Pat. No. 4,246,253. In U.S. Pat. No. 4,828,834 Nagaura et al. attempted to prepare lithium manganese oxide materials by sintering precursor lithium salt and MnO.sub.2 materials. However, Nagaura's nominal LiMn.sub.2 O.sub.4 compounds were not fully crystallized spinel electrodes and suffered from very low capacity. The methods described by Hunter and Nagaura require a heating time of from about 10 to about 50 hours at temperatures ranging from about 500.degree. C. to about 900.degree. C. Accordingly, present methods for forming lithium manganese oxide, nominally, LiMn.sub.2 O.sub.4, pose significant barriers due to the severe penalty of time, controlled process conditions, and other features which do not permit adaptability to automated commercial production.